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1.
Bull Entomol Res ; 107(6): 756-767, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28382881

RESUMO

The optimal use of available host by parasitoid insects should be favoured by natural selection. For solitary parasitoids, superparasitism (i.e. the egg-laying of several eggs/host) may represent a detrimental phenomenon both in a biological and an applied sense, but under certain circumstances it may be adaptive. Here, we studied the effects of increasing levels of superparasitism (LSPs, number of parasitoid larvae/host) on fitness-related parameters of the immature and adult stages of Diachasmimorpha longicaudata, a solitary endoparasitoid parasitizing Ceratitis capitata. We investigated the moment when supernumerary parasitoid larvae are eliminated and the effects produced by this process, together with its repercussion on female fecundity, parasitism rate, sex ratio, adult survival, flight ability and body size. Complete elimination of competitors occurred soon after larval hatching, before reaching the second larval stage. Elimination process took longer at higher LSPs, although a normal developmental (egg-adult) time was achieved. For LSPs 1, 2, 3 and 5 the effects on parasitoid emergence were mild, but LSP 10 led to the death of all developing parasitoids. Aside from this, to develop in superparasitized hosts did not significantly affect any of the evaluated parameters, and only a female-biased sex ratio was observed at higher LSPs. However, the effects of superparasitism on the adults may have a different outcome under more variable conditions in the field, once they are released for biological control purposes.


Assuntos
Ceratitis capitata/parasitologia , Interações Hospedeiro-Parasita , Vespas/crescimento & desenvolvimento , Animais , Tamanho Corporal , Feminino , Fertilidade , Voo Animal , Masculino , Razão de Masculinidade
2.
Bull Entomol Res ; 103(3): 310-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23340454

RESUMO

The sterile insect technique (SIT) has been proposed as an area-wide method to control the South American fruit fly, Anastrepha fraterculus (Wiedemann). This technique requires sterilization, a procedure that affects, along with other factors, the ability of males to modulate female sexual receptivity after copulation. Numerous pre-release treatments have been proposed to counteract the detrimental effects of irradiation, rearing and handling and increase SIT effectiveness. These include treating newly emerged males with a juvenile hormone mimic (methoprene) or supplying protein to the male's diet to accelerate sexual maturation prior to release. Here, we examine how male irradiation, methoprene treatment and protein intake affect remating behavior and the amount of sperm stored in inseminated females. In field cage experiments, we found that irradiated laboratory males were equally able to modulate female remating behavior as fertile wild males. However, females mated with 6-day-old, methoprene-treated males remated more and sooner than females mated with naturally matured males, either sterile or wild. Protein intake by males was not sufficient to overcome reduced ability of methoprene-treated males to induce refractory periods in females as lengthy as those induced by wild and naturally matured males. The amount of sperm stored by females was not affected by male irradiation, methoprene treatment or protein intake. This finding revealed that factors in addition to sperm volume intervene in regulating female receptivity after copulation. Implications for SIT are discussed.


Assuntos
Controle de Insetos/métodos , Metoprene/toxicidade , Comportamento Sexual Animal/fisiologia , Tephritidae/fisiologia , Análise de Variância , Animais , Argentina , Proteínas Alimentares/farmacologia , Feminino , Fertilidade/efeitos da radiação , Raios gama , Masculino , Pupa/efeitos da radiação , Comportamento Sexual Animal/efeitos dos fármacos
3.
Bull Entomol Res ; 103(1): 1-13, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22929968

RESUMO

Sexual maturation of Anastrepha fraterculus is a long process. Methoprene (a mimic of juvenile hormone) considerably reduces the time for sexual maturation in males. However, in other Anastrepha species, this effect depends on protein intake at the adult stage. Here, we evaluated the mating competitiveness of sterile laboratory males and females that were treated with methoprene (either the pupal or adult stage) and were kept under different regimes of adult food, which varied in the protein source and the sugar:protein ratio. Experiments were carried out under semi-natural conditions, where laboratory flies competed over copulations with sexually mature wild flies. Sterile, methoprene-treated males that reached sexual maturity earlier (six days old), displayed the same lekking behaviour, attractiveness to females and mating competitiveness as mature wild males. This effect depended on protein intake. Diets containing sugar and hydrolyzed yeast allowed sterile males to compete with wild males (even at a low concentration of protein), while brewer´s yeast failed to do so even at a higher concentration. Sugar only fed males were unable to achieve significant numbers of copulations. Methoprene did not increase the readiness to mate of six-day-old sterile females. Long pre-copulatory periods create an additional cost to the management of fruit fly pests through the sterile insect technique (SIT). Our findings suggest that methoprene treatment will increase SIT effectiveness against A. fraterculus when coupled with a diet fortified with protein. Additionally, methoprene acts as a physiological sexing method, allowing the release of mature males and immature females and hence increasing SIT efficiency.


Assuntos
Proteínas Alimentares , Hormônios Juvenis , Metoprene , Controle Biológico de Vetores/métodos , Comportamento Sexual Animal/efeitos dos fármacos , Tephritidae , Ração Animal , Animais , Suplementos Nutricionais , Feminino , Masculino , Controle Biológico de Vetores/economia , Pupa/crescimento & desenvolvimento , Maturidade Sexual/efeitos dos fármacos , Tephritidae/crescimento & desenvolvimento
4.
J Insect Physiol ; 101: 7-14, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28623148

RESUMO

The juvenile hormone (JH) of insects triggers physiological changes related to reproduction in adults of both sexes. Methoprene is a sesquiterpene with some effects that are analogous to those of JH. Treatments with methoprene accelerate sexual maturation in males of the South American fruit fly Anastrepha fraterculus, giving young males a mating advantage over non-treated males of the same age. Here, we evaluated the effects of methoprene treatment on A. fraterculus males after the sexual maturation phase and tested whether this compound provides a long-term mating advantage. Moreover, we took the first step to unravel the mechanisms that underlie male sexual enhancement. We treated males 1day or 8days after adult emergence and compared mate choice between recently matured (young) females and females that had been mature for ca. 10days (aged females). We also addressed methoprene treatment effects on male sexual signalling. We found that methoprene treatment enhanced male sexual competitiveness even after the sexual maturation phase, and the effect did not decrease until males were older than 20days. However, when methoprene treatment was carried out close to sexual maturity, the mating enhancement was no longer observed, suggesting a non-immediate effect and excluding the possibility that methoprene acts as a pheromonal compound. Young and aged females tended to mate more frequently with treated-males. This might indicate that in a context of sexual selection, the potential benefits associated with reproductive success would be similar for females of both ages. Treated males released larger amounts of pheromonal compounds than non-treated males, but their courtship behaviour was not altered to the same extent, suggesting that methoprene treatment may accelerate differently the components of male courtship. We discuss potential benefits of using methoprene to increase the efficiency of the sterile insect technique, which is an environmentally safe method to control this important South American fruit pest.


Assuntos
Hormônios Juvenis/farmacologia , Metoprene/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Maturidade Sexual , Tephritidae/efeitos dos fármacos , Tephritidae/fisiologia , Animais , Feminino , Masculino
5.
Genome ; 38(6): 1091-7, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8654910

RESUMO

In this paper we analyze genetically and cytologically a Y-chromosome 2 translocation with several markers, some of which are potentially useful for large scale sex separation. The breakpoint of this Y-2 translocation is located at region 6B on the trichogene polytene chromosome map. It is found that, in strains carrying this TY-2, only 40% of the fertilized eggs survived to the adult stage, 26% of them dying as embryos, 27% as larvae, and 7% as pupae. Early lethality is explained by the nonviability of adjacent-1 products of meiosis containing a deletion of section 1A-6B. The reciprocal segregation products, carrying this chromosome segment in triplicate, survive until late stages. By analyzing the phenotype of the individuals we conclude that all markers used in this study are located outside the triplicated region and that the male determining factor is not included in the piece of the Y chromosome translocated to chromosome 2. The male recombination frequencies of several genes located on chromosome 2 relative to the breakpoint of translocation T5038 have also been studied here.


Assuntos
Mapeamento Cromossômico , Dípteros/genética , Translocação Genética/genética , Cromossomo Y , Animais , Cruzamentos Genéticos , Dípteros/embriologia , Dípteros/crescimento & desenvolvimento , Feminino , Marcadores Genéticos , Larva , Masculino , Mutação , Pupa , Diferenciação Sexual
6.
Genetica ; 116(1): 85-95, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12484528

RESUMO

This report deals with the process of improving the stability of medfly, Ceratitis capitata, genetic sexing strains (GSS) based on the sw mutation on chromosome 2. This gene affects the rate of development as well as the eye colour and iridescence. The improved sexing strains were produced by mapping sw with deletions and then inducing and screening for new translocations with breakpoints close to the marker. The stability was assessed in large populations over many generations. Twenty-two new Y-2 translocations were identified and polytene chromosome analysis was performed to locate breakpoints. The translocation strains were ranked according to the distance of their breakpoints from sw. The map position of sw is region 20D on 2R. As data on the stability of the 22 strains accumulated, Cast 191 was shown to be the most promising as no recombination between sw and the male sex was found. After rearing the strain for 22 generations under semi-mass rearing conditions, with a population size of 15,000 adults and scoring 1000 flies per generation, only one such event was detected (estimated frequency = 3.1 x 10(-6)). Further tests are being carried out with this strain to assess its suitability as a genetic sexing strain for medfly Sterile insect technique (SIT).


Assuntos
Ceratitis capitata/genética , Genes de Insetos , Pré-Seleção do Sexo/métodos , Animais , Cruzamento , Ceratitis capitata/efeitos da radiação , Bandeamento Cromossômico , Quebra Cromossômica , Mapeamento Cromossômico , Cromossomos/genética , Cromossomos/efeitos da radiação , Cromossomos/ultraestrutura , Feminino , Marcadores Genéticos , Infertilidade Masculina/genética , Masculino , Controle Biológico de Vetores/métodos , Deleção de Sequência , Translocação Genética/genética , Cromossomo Y/genética , Cromossomo Y/ultraestrutura
7.
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